The
Mi croscope
Compound Microscope
(lesson objectives)
• Be able to identify the parts and functions of
the compound microscope.
• Be able to explain the procedures to making a
wet mount slide.
• Be able to calculate total magnification.
COMPOUND
MICROSCOPE
• Compound = 2 lenses
– Ocular Lens (10x)
– Objective Lens (4x,10x,40x)
Image is spun upside-down
and backwards.
Microscope Parts
Eyepiece/Ocular
Coarse Adjustment
Fine Adjustment
Arm
Stage Clips
Body Tube
Nose Piece
Low Power Objective
High Power Objective
Stage
Diaphragm
Base
Light
Functions
1. OBJECTIVE LENSES
2. EYEPIECE (Ocular)
3. DIAPHRAGM
4. STAGE
5. COARSE ADJUSTMENT
6. FINE ADJUSTMENT
Using the Microscope!!
HOW TO USE
1.
Set the microscope to the lowest power objective.
2.
coarse adjustment
Lower the stage all the way using the ____________________.
3.
Place the ____________
slide on the ________________.
stage
4.
Use the ________
coarseadjustment to bring the stage all the way up.
5.
Then focus on the object using the coarse adjustment.
6.
Then use the ____________
fine adjustment to focus better.
7.
Find what you are looking for and place it in the center of the field of
view.
8.
stage by using the __________
Lower the ____________
adjustment.
coarse
9.
Switch to the ___________
high power objective.
fine adjustment
10. Then focus, using only the _______________________.
Rules
1. Always use lowest power to scan
the slide for the specimen.
Rules
2. Never use coarse
adjustment with
high power
objective!
Finding Total Magnification
Ocular Lens
X
Objective Lens
LP= 150x
HP= 450x
What is the lowest possible magnification that
can be obtained using the microscope
shown?
1.
2.
3.
4.
20x
200x
10x
100x
Field of View
• The area that can be seen
through the microscope.
100x
400x
• Is the field of view larger or
smaller under high power?
FOV
• The lower the magnification, the Larger the
Field of view.
• The higher the magnification, the smaller the
field of view.
What do you notice about the amount of
light when you switch from low power to
high power?
• There is less light.
• You need to adjust the
diaphragm.
Field of View
• Under high power: The FOV is
SMALLER and DARKER!
Depth of Field: the
level you are
focused on
A Paramecium
moves to different
levels of depth
when it swims
Depth of field
• Use the fine adjustment knob to get to the
depth that you want to see.
How to make a wet mount
• 1. Place specimen on a glass slide.
• 2. add a drop of water
• 3.Lower glass cover slip on an angle to avoid
air bubbles.
• 4. examine under low power.
• Note: if stain is to be used, place drop of
stain on one side of slide and pull it through
using a paper towel.
Note: if stain is to be used, place drop
of stain on one side of slide and pull it
through using a paper towel.
• Two common stains which are commonly
used are:
• METHELYNE BLUE
IODINE
How to Make a Wet Mount
To avoid air
bubbles under
your slide,
touch the
coverslip to
the drop then
lower it slowly,
squeezing the
drop.
Microscope Lab
Examine the
functions and
magnification
of your
microscope.
Microscope Lab
A.
B.
C.
D.
E.
Get to know the microsope.
Wet Mount of “e”.
Wet Mount of colored paper.
Look at 2 hairs.
2 more slides.
e
The diagram represents a hydra as
viewed with a compound light
microscope. If the hydra moves to the
right of the slide preparation, which
diagram below best represents what will
be viewed through the microscope?
The diagram to the left represents
the letter "h" as seen in the low
power field of view of a compound
light microscope. Which diagram
below best represents the field of
view if the slide is not moved and the
objective is switched to high power?